The invention relates to an extrudable adhesive composition of ethylene copolymer, modified ethylene copolymer, styrene polymer, and saturated alicyclic hydrocarbon resin, useful for bonding polystyrene to barrier polymers.
Copending U.S. patent application No. 07/202,033, filed June 3, 1988 by the present inventor, discloses a blend of ethylene vinyl acetate copolymer, ethylene vinyl acetate copolymer modified by grafting with a comonomer containing pendant acid or acid derivative functionality, and impact modified polystyrene, which provides a useful adhesive, particularly for bonding polystyrene to gas barrier polymers.
Similar adhesive systems for laminates are known in the art. For example, Japanese application No. 53 018 653, to Imura et al., discloses a resin composition which is obtained by mixing 3-100 parts by weight of a hydrogenated petroleum resin with 100 parts by weight of an ethylene carboxylate-vinyl acetate copolymer which has been obtained by copolymerizing an unsaturated carboxylic acid and/or its anhydride with at least one vinylidene monomer in the presence of an ethylene-vinyl acetate copolymer.
U.S. Pat. No. 4,670,349, to Nakagawa et al., discloses an adhesive resin composition of (A) an ethylene vinyl acetate or ethylene alpha-olefin random copolymer, (B) a modified polyethylene containing 0.01 to 10% by weight of an unsaturated carboxylic acid or its derivative grafter thereto, and (C) 1 to 125 parts by weight of a hydrogenated aromatic petroleum resin. The resin is suitable as an adhesive for laminating polystyrene to ethylene vinyl alcohol copolymer.
U.S. Pat. No. 4,358,557, to Boggs, discloses a hot-melt adhesive composed of ethylene vinyl acetate copolymer, a tackifier selected from hydrocarbon resin, polyterpene resin or rosin ester, a paraffin wax and an aromatic hydrocarbon resin.
U.S. Pat. No. 3,932,332, to Douglas et al., discloses an adhesive of ethylene vinyl acetate copolymer, a paraffin wax and a copolymer of styrene and alpha-methyl styrene.
U.S. Pat. No. 4,576,995, to Nakabayashi et al., discloses an adhesive for bonding ethylene/vinyl alcohol copolymer and polystyrene, which comprises a modified ethylene/vinyl acetate copolymer obtained by graft-copolymerizing a styrenic vinyl monomer and an alpha, beta-unsaturated carboxylic acid to an ethylene/vinyl acetate copolymer. Laminates prepared therefrom are valuable as a deep draw forming material with enhanced gas barrier properties.
Japanese application No. 54057582 (reported as Derwent Abstract No. 46260B/25) discloses a resin laminate of a polystyrene resin layer, a layer of ethylene-vinyl acetate copolymer saponification product, and a layer of a styrene/butadiene block copolymer containing 60% butadiene, ethylene vinyl acetate copolymer (6 mol % VA), and a maleic anhydride-ethylene vinyl acetate graft copolymer.
Japanese application No. 58203043 (reported as Derwent Abstract No. 84-008480/02) discloses a similar laminate, in which the adhesive layer is a blend of polystyrene, ethylene-vinyl acetate copolymer (5-50% VA), and a polyolefin grafted with e.g. maleic anhydride.
Japanese application No. 59055743 discloses a process for production of resin laminates characterized by melt coextrusion of a styrene group resin layer, a gas barrier resin layer such as saponified ethylene-vinyl acetate copolymer, and a bonding layer of (a) ethylene-vinyl acetate copolymer graft-modified with unsaturated carboxylic acid or anhydride, and (b) ethylene-vinyl acetate copolymer which is graft-modified with e.g. styrene, or further (c) unmodified ethylene-vinyl acetate copolymer.